body #player #theater-background,
body.ytcenter-player-darkside-bg #player.watch-small #theater-background {
  display: none;
}

body.ytcenter-player-darkside-bg #player #theater-background {
  display: block;
  position: absolute;
  left: 0;
  margin-top: 0;
  width: 100%;
  -moz-transition: background-color .3s ease;
  -webkit-transition: background-color .3s ease;
  transition: background-color .3s ease;
  background-color: #1B1B1B; /* Yes, we have cookies */
}

body.ytcenter-player-darkside-bg.ytcenter-player-darkside-bg-retro #player #theater-background {
  background-color: #444;
  background-image: -moz-linear-gradient(top, #555, #333);
  background-image: -webkit-gradient(linear, left top, left bottom, from(#555), to(#333));
  filter: progid:DXImageTransform.Microsoft.Gradient(gradientType=0, startColorStr='#555555', endColorStr='#333333');
}

body.ytcenter-player-darkside-bg #player {
  background-color: #1B1B1B;
}